1. Field of the Invention
This invention relates to oral and nasal intubation devices and more particularly to a stylet and method of use for both oral and nasal intubation with an endotracheal tube.
2. Description of Related Art
Endotracheal tubes are utilized in a wide variety of medical procedures to provide an unobstructed air passage to a patient's trachea. In many emergency situations it is necessary to intubate a patient as quickly as possible to provide a secure airway to the patient's lungs or permit forced ventilation thereof while preventing introduction of gastric contents. Failure to quickly supply oxygen to the lungs can result in brain damage or death of the patient.
Endotracheal tubes are used orally and nasally to establish an open airway. Intubation is often difficult because of the contours and obstacles encountered in the patient's airway. Perhaps the most difficult step in intubating a patient is maneuvering the tube into the patient's trachea rather than the patient's esophagus.
Endotracheal tubes are generally formed of a soft, pliable plastic materials. Most endotracheal tubes do not have sufficient strength or rigidity to permit intubation without the aid of a stylet or other manipulating device. Making the endotracheal tube out of a stiffer material is not an acceptable alternative because it would cause excessive trauma to the nasal or throat tissue. The accepted solution has been the use of a stylet telescopically received within the endotracheal tube.
The stylet which has gained the most acceptance for oral intubation is a "pre-bend" stylet made of a rigid, malleable material such as rubber-coated metal. To intubate a patient with any stylet, the patient must first be hyperventilated for approximately three to four minutes. Next, the user inserts the stylet into the tube and folds one end of the stylet around the outboard end of the endotracheal tube. The user grasps the tube and the stylet and bends the tube to approximate what the user believes the contour of the patient's throat to be. With the help of a laryngoscope, the user inserts the stylet and endotracheal tube into the patient's mouth and throat until it reaches the patient's trachea. Unfortunately, without years of experience, it is difficult for a user to obtain the proper pre-bend in the malleable stylet and successfully insert the endotracheal tube into the patient's trachea. To complicate this further, each patient's airway is different.
If the user fails to intubate the patient on the first attempt, she must remove the tube and stylet from the patient, grasp the tube and stylet, rebend it accordingly, re-ventilate the patient and again insert the tube and stylet into the patient.
One problem with the malleable stylet is the valuable time lost as the user ventilates the patient and reinserts the tube and stylet repeatedly. Secondly, repeated insertions of the tube and stylet damages the patient's soft airway tissue. Finally, the malleable stylet sacrifices sterility of the endotracheal tube when the user grasps the tube and stylet to bend and rebend the stylet.
Mechanical guides have been developed to assist intubation of endotracheal tubes. However, none of these stylets have met with widespread commercial success or recognition in the medical field. The malleable or "prebend" stylet is still the predominate oral intubation aid used.
One example of a mechanical intubation guide is seen in U.S. Pat. No. 4,329,983 issued May 18, 1982, to Fletcher. The guide of Fletcher comprises a flexible bar and flexible line wherein the line extends both through and along the bar. One end of the line is attached to one end of the bar and the other end of the line is attached to a pivotable toggle offset from the axis of the flexible bar. Because the user is typically holding the laryngoscope in one hand for oral intubation, she only has one hand free to manipulate the intubation guide. The pivotable toggle mechanism of Fletcher is difficult if not impossible to manipulate with one hand. In addition, the pivotable toggle of Fletcher makes it difficult to control the end of the flexible bar and feel the flexible bar and tube during intubation. The ability to feel and control the movement of the stylet and endotracheal tube is vital for quick intubation and to avoid damaging the sensitive tissues encountered during intubation.
Another example of a mechanical intubation mechanism with an offset actuator is disclosed in U.S. Pat. No. 4,529,400 issued Jul. 16, 1985, to Scholten. This mechanism utilizes a chain-link stylet which is manipulated by a pivotable handle offset from the axis of the stylet. Once again, the pivotable handle of this mechanism suffers from a lack of delicate control and sensitivity helpful in successfully intubating a patient quickly with a minimum amount of trauma to sensitive tissue.
Another example of a mechanical intubation device is disclosed in U.S. Pat. No. 4,949,716 issued Aug. 21, 1990, to Chenoweth. This mechanical device is utilized for nasal intubation and utilizes a cooperable spring and wire mounted within a plastic sheath. As with the other stylet devices, the handle for manipulating the stylet is offset from the axis of the stylet thereby eliminating the control and sensitivity necessary to successfully intubate the patient.